Method of producing lenticular embossing rolls



United States Patent 3,380,864 lvIETHOD OF PRODUCING LENTICULAR EMBOSSING ROLLS Frank W. Broderick, P.O. Box 2, Stirling, NJ. 07980 Filed Jan. 13, 1965, Ser. No. 425,334 3 Claims. c1. 156-14) ABSTRACT OF THE DISCLOSURE The method of producing an embossing roll whereby an optimum lenticular reflecting surface is produced including etching a design area in a roll in which broad parallel lines produce different reflective angles; coating the roll with a first acid resist and doctoring off the surface the resist so that etching remains filled with the first resist; spray coating the exposed roll surface with a second acid resist and etching the sprayed surface to a degree necessary to produce a mist surface on the outer surface of the roll, among the first acid resist and mating another roll with the prepared roll whereby embossing a foil produces an embossment having shiny upper surfaces and duller valleys on lower surfaces.

This invention relates to lenticular engraved rolls and to the novel method of preparation and to the novel product of said roll.

The figure of the drawing is a flow diagram with legends.

The prior art has developed techniques in lenticular line engraving used in embossing plates for Christmas, Easter and similar greeting cards. Such embossing is done on foil with registered transparent colors overprinting the lenticular reflecting surface in such a manner that a different reflectivity is obtained whenever the angle of perception is changed. Such embossing has been accepted in great demand for gift packaging purposes in this country but manufacturers could not procure the necessary embossing cylinders for high speed rotary presses, due to the impossibility of securing satisfactory engraving at a practical cost.

Various attempts have been made to produce such embossing rolls 'by means of photoengraving but the angular joinings of the reflective lines did not blend with the background with the result that only crude reproductions were obtained. Attempts to obtain better results by machine engraving having the primary tooling cut by hand resulted in costs that were prohibitive to users of modern packaging.

According to this invention, a new photoengraving process is developed which eliminates the disadvantages of the prior art and thus is economical and is designed for use in high speed rotary equipment.

It is an object of this invention to produce by a novel method of lenticular embossing roll to provide an embossed metal foil or laminate sheet having a pleasing design set forth therein by means of various areas of lenticular or parallel lines interspersed with areas of frost-like appearance.

It is another object of the invention to provide a novel method to provide novel engraved rolls adapted to emboss areas of lenticular or parallel lines interspersed with areas of frost-like or grainy appearance.

These and other objects of this invention will become apparent upon reading the following descriptive disclosure.

The figure of the drawing shows a flow diagram illustrating the successive steps of the invention.

According to this invention, the original artists color presentation is prepared in the conventional manner. A transparent overlay is prepared in the conventional manice ner with various areas of parallel transparent line overlays or decalcomania, said lines being relatively broad and evenly spaced and having a density of from about 40 to about lines per inch are arranged in a pleasing manner to form for example, a scene having a sky, several trees, houses and so forth. The sky having horizontal lines, the clouds having curved lines, the trees having vertical lines, the roofs having diagonal lines, etc. After all the areas of lines are in position we have the equivalent of a black and white drawing. This drawing is photographed in the conventional manner to produce a negative and in the event that more than one duplicate scene is required for the roll, the primary negative is photo composed to Whatever number is required.

As seen in the drawing, the photo-composed film is then used in the conventional way to photo-engrave the lines to an acid etched depth of from .002 to .005 inch into a conventional metal production cylinder. At this point the area borders or joinings of the lines would be crude and hence would not pleasingly blend together. The photo-engraved roll is now solidly coated with an acid resist and excess resist is then doctored off in such a manner that all of the etched line cavities remain filled with resist and the unetched portions of the roll appear as clean and bright metal. The roll is then sprayed with a. turpentine or similar soluble acid resist so that the bright metal portions now have a misty appearance. By varying the viscosity of the turpentine or similar soluble resist, the spray pressure and the nozzle openings various density patterns of this mist may be obtained. The roll is then etched a time interval necessary to obtain the desired depth effects. Surface finishes from fine satin appearance to a coarse emery appearance are easily etched in this manner.

Where two or more turpentine soluble spray etchings are necessary to produce a desired effect, the etched lines may be filled first with a methyl ethyl ketone soluble acid resist having a dilferent solvent action than that of the turpentine soluble spray mist acid resist. By so doing the spray resist may be etched, removed with turpentine without removing the ketone soluble resist, and then be resprayed and re-etched in order to give various levels of etched depth with resulting greater surface area and greater reflectivity.

In lieu of the ketone soluble resist used in combination with a turpentine soluble resist, other resist combinations of dissimilar solvency may be used in this invention.

After the top areas of the lines and other desired top areas are finished with the mist-like reflective surface, the crudeness of the joining borders of the area of the lines has disappeared and the final product is an embossing of smooth and evenly blended appearance. This roll may then be mated by conventional means to a paper filled roll or to a matching male steel roll for high speed rotary production. The finished embossed foil produced by the roll or rolls of this invention have the raised portion of all lines smooth and shiny, whereas the indent portions of the lines have an emery or mist-like reflection. Because of the arrangement of the lines of the various areas, the various angles of perception of the viewer causes an apparent movement within the pattern of smoothly and pleasingly blended lined areas.

I claim: 1. The method of producing a lenticular embossing roll for use on a rotary press comprising the steps of: (a) etching a steel roll and producing first design areas having different reflective angles by means of relatively broad, parallel lines at a depth from .002 to .005 inch;

(b) coating said roll and filling said etched lines with a first acid resist of the class soluble in methylethyl ketone, acetone and toluol;

(c) mechanically removing said first acid resist only from the surface of said roll and exposing the metal between said etched lines and permitting said first acid resist to remain only in said etched lines;

(d) mist-spraying said exposed metal at least once with a second acid resist of the class soluble in turpentine;

(e) acid etching said roll and producing mist-like second areas;

(f) removing said second acid resist at least once without disturbing said first acid resist; and

(g) removing said first acid resist whereby the roll has an engraved surface for producing lenticular embossings in which adjacent design areas merge smoothly and pleasuringly to the eye and mist-like reflective areas are provided on top surfaces between adjacent parallel lines.

2. The method as claimed in claim 1 in which said parallel lines are produced in a density from 40 to 80 lines per inch. 7

3. The method as claimed in claim 1 including the step of removing and reapplying said second acid resist 5 more than once.

References Cited UNITED STATES PATENTS 3,105,783 10/1963 Parkinson 15614 3,210,186 10/1965 Gorig 96-32 10 3,257,251 6/1966 Lewis et a1. 156-8 3,268,378 8/1966 Broderick 15614 OTHER REFERENCES 1? Rolls for Embossing Release from Eastern Engraving a Machine Co., Inc., 1961, Copy in 156-14.

JACOB STEINBERG, Primary Examiner. 

